[openjudge] jubeeeeeat

http://cdqz.openjudge.cn/2016/0003/

shabi建图，shabi网络流

#include <bits/stdc++.h>
#include <queue>

using namespace std;
const int N = 3010;
const int M = 5e5 + 10;

#define gc getchar()
#define oo 999999999

int n, m, p, now, S, T;
int dis[N], head[N], now_head[N];
bool H[N][N];
int B[N][N];
struct Node{
    int u, v, cap, nxt;
}G[M];
queue <int> Q;

inline int read(){
    int x = 0, f = 1; char c = gc;
    while(c < '0' || c > '9') {if(c == '-') f = -1; c = gc;} 
    while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = gc;
    return x * f;
}

inline void add(int u, int v, int cap){
    G[now].v = v; G[now].cap = cap; G[now].nxt = head[u]; head[u] = now ++;
}

inline bool bfs(){
    for(int i = S; i <= T; i ++) dis[i] = -1, now_head[i] = head[i];
    dis[S] = 0;
    while(!Q.empty()) Q.pop();
    Q.push(S);
    while(!Q.empty()){
        int topp = Q.front();
        Q.pop();
        for(int i = head[topp]; ~ i; i = G[i].nxt){
            int v = G[i].v;
            if(dis[v] == -1 && G[i].cap > 0){
                dis[v] = dis[topp] + 1;
                if(v == T) return 1;
                Q.push(v);
            }
        }
    }
    return 0;
}

int dfs(int now, int flow){
    if(now == T) return flow;
    int f, ret = 0;
    for(int & i = now_head[now]; ~ i; i = G[i].nxt){
        int v = G[i].v;
        if(dis[v] == dis[now] + 1 && G[i].cap > 0){
            f = dfs(v, min(G[i].cap, flow - ret));
            if(f){
                G[i].cap -= f;
                G[i ^ 1].cap += f;
                ret += f;
                if(ret == flow) break;
            }
        }
    }
    if(ret != flow) dis[now] = -1;
    return ret;
}

inline int Dinic(){
    int answer = 0;
    while(bfs()) answer += dfs(S, oo);
    return answer;
}

inline void add_I(int x, int y, int l, int u){
    for(int i = x; i <= x + l - 1; i ++)
        for(int j = y; j <= y + l - 1; j ++)
            if(H[i][j]) add(u, B[i][j], 1), add(B[i][j], u, 0);
}

inline void build(){
    for(int i = 1; i <= n; i ++) 
        for(int j = 1; j <= n; j ++)
            if(H[i][j]) add(B[i][j], T, 1), add(T, B[i][j], 0);
    for(int i = 1; i <= m; i ++){
        int x = read(), y = read(), z = read();
        add_I(x, y, z, i);
    }
    for(int i = 1; i <= m; i ++) add(0, i, 5), add(i, 0, 0);
}

int main()
{
    n = read(); m = read(); p = read();
    T = m; 
    int js(0);
    for(int i = 1; i <= n; i ++) 
        for(int j = 1; j <= n; j ++) {
            H[i][j] = read();
            if(H[i][j]) js ++, B[i][j] = T + 1, T ++;
    }
    T ++, S = 0;
    for(int i = 0; i <= T; i ++) head[i] = -1;
    build();
    int ans = Dinic();
    int answer = min(js, ans + p);
    cout << answer;
    
    return 0;
}
/*
3 1 3
1 0 1
1 1 1
1 0 1
1 1 2
*/